The Magnesium Correction Calculator gives weight-based dosing for IV and oral magnesium replacement in hypomagnesaemia. The app's own reference states magnesium should be corrected when the level is below 0.75 mmol/L, and provides a standard bolus dose, a slower infusion option for stable patients, and an oral maintenance dose. It also includes toxicity monitoring guidance and a framework for working up the cause of magnesium loss.
The app's reference states correction is indicated when magnesium is below 0.75 mmol/L.
0.2 mmol/kg (equivalent to 50 mg/kg, or 0.5 mL/kg of 10% MgSO₄), to a maximum of 4 mmol, 1 g, or 10 mL, given over 10 minutes.
For stable patients, the app calculates MgSO₄ 25–50 mg/kg IV given over 2–4 hours.
The app lists bradycardia, hypotension, and loss of deep tendon reflexes, noting toxicity typically occurs at levels of 4 mmol/L or higher, and advises stopping the infusion if reflexes are absent or blood pressure drops.
It notes a fractional excretion of magnesium (FE_Mg) below 2% suggests non-renal loss (GI, dietary), while a 24-hour urine magnesium above 30 mg suggests renal loss from diuretics, tubulopathies, alcoholism, or drug effects.